A table-based bias and temperature-dependent small-signal and noiseequivalent circuit model

A new algorithm is presented for construction of accurate table-based bias and temperature dependent field-effect transistor (FET) small-signal and noise models. The algorithm performs two-dimensional (2-D) linear interpolation on a single stored data table to quickly produce bias and temperature-dependent model simulations. Comparisons of simulated FET S-parameters, noise figure, and device figures of merit (e.g., G_max) versus measured data show the model to be accurate over a wide range of bias and temperatures. Model enabled simulations of a single-stage FET-based low-noise monolithic microwave integrated circuit (MMIC) amplifier are also shown to compare favorably with measured amplifier data. The new algorithm improves on previously available approaches in three ways: (1) it allows efficient and accurate small signal device and circuit simulations over bias and temperature; (2) it allows circuit optimization with respect to bias and temperature; and (3) it provides substantial data storage reduction over alternate approaches. Because one compact data table represents a single sample device, the approach can be readily adapted for use in a statistical FET model data base     

南非伊斯科公司纽卡索厂综合二级自动化系统

奥钢联工程技术公司（ＶＡＩ）为南非伊斯科公司纽卡索厂炼钢车间（包括３座转炉,２座钢包炉,１套真空脱气装置和２台连铸机）安装了一套综合二级自动化系统。（ＶＡＩ－Ｑ Ｂｌｏｏｍ）综合质量控制系统通过监控从炼钢到连铸的整个生产过程,确保成品达到高质量水平。还提供了一台连铸机培训模拟器,用于训练操作人员。     

OverMesh: network-centric computing [Accepted from Open Call]

The communications industry significantly lags behind the personal computing industry in terms of empowering the end user to innovate, as fundamental architectural shifts have yet to occur to push intelligence to the network edge. The decentralization of the telecommunication system to the edge of today's hierarchically formed networks is inevitable with the emergence of key wireless technologies and the proliferation of mobile computing devices and more prevailing usage models. This article envisions a decentralized communication system formed of wireless mesh networks and a highly virtualized, converged computing and communications node-based architecture with emergent management capabilities. We propose to embed the user inside the network to freely associate services and resources such as computing, storage, and bandwidth to rapidly advance network innovation - network-centric computing. This article proposes a novel direction and vision for network-centric computing, expands upon our research, and presents the OverMesh platform from which we have begun work to instantiate this vision. Finally, we expect this new envisioned network to coexist with today's Internet infrastructure and enable a new generation of applications and usage models     

Modified Joint Weibull approach to determine Load Enhancement Factors

Load Enhancement Factor (LEF) and similar statistical methods have been used for decades to reduce the time and cost associated with component-level fatigue testing on aerospace structures. The most common LEF approach was that developed by the Naval Air Development Corporation in the 1980s. Though considered an innovative and novel concept at its conception, this traditional method has a number of limitations that restrict its applicability to only a handful of testing scenarios. The objective of this study was to deal with those restrictions and offer a more comprehensive approach to account for modern advances in statistics, composite materials, and testing technology. The formulation of the new method uses the traditional LEF method as a foundation, but uses a revised set of notation and incorporates a modified Joint Weibull analysis technique to improve its potency. A detailed set of sample calculations using stochastically generated data illustrates how the computations are performed, thus allowing practitioners to reproduce the method using their own data. A short discussion also addresses some common misconceptions regarding the use of Load Enhancement Factors.     

Math methods in transistor modeling: Condition numbers forparameter extraction

Condition numbers expressing the sensitivity of computed circuit element values to inaccuracies in S-parameter measurements are derived and evaluated for a standard small-signal MESFET model. The condition numbers shed light on the common difficulty experienced by transistor modelers in extracting accurate values for the input resistance. Other elements are also classified according to their sensitivity     

Treating landfill leachate using passive aeration trickling filters; effects of leachate characteristics and temperature on rates and process dynamics

Biological ammoniacal-nitrogen (NH₄⁺-N) and organic carbon (TOC) treatment was investigated in replicated mesoscale attached microbial film trickling filters, treating strong and weak strength landfill leachates in batch mode at temperatures of 3, 10, 15 and 30 °C. Comparing leachates, rates of NH₄⁺-N reduction (0.126-0.159 g m^− 2 d^− 1) were predominantly unaffected by leachate characteristics; there were significant differences in TOC rates (0.072-0.194 g m^− 2 d^− 1) but no trend relating to leachate strength. Rates of total oxidised nitrogen (TON) accumulation (0.012-0.144 g m^− 2 d^− 1) were slower for strong leachates. Comparing temperatures, treatment rates varied between 0.029-0.319 g NH₄⁺-N m^− 2 d^− 1 and 0.033-0.251 g C m^− 2 d^− 1 generally increasing with rising temperatures; rates at 3 °C were 9 and 13% of those at 30 °C for NH₄⁺-N and TOC respectively. For the weak leachates (NH₄⁺-N < 140 mg l^− 1) complete oxidation of NH₄⁺-N was achieved. For the strong leachates (NH₄⁺-N 883-1150 mg l^− 1) a biphasic treatment response resulted in NH₄⁺-N removal efficiencies of between 68 and 88% and for one leachate no direct transformation of NH₄⁺-N to TON in bulk leachate. The temporal decoupling of NH₄⁺-N oxidation and TON accumulation in this leachate could not be fully explained by denitrification, volatilisation or anammox, suggesting temporary storage of N within the treatment system. This study demonstrates that passive aeration trickling filters can treat well-buffered high NH₄⁺-N strength landfill leachates under a range of temperatures and that leachate strength has no effect on initial NH₄⁺-N treatment rates. Whether this approach is a practicable option depends on a range of site specific factors.     

Sterol ester hydrolase inFusarium oxysporum

Two electrophoretically different forms of sterol ester hydrolase (EC 3.1.1.13) were obtained from the cytoplasmic extract of the mycelia ofFusarium oxysporum. The entities, estimated at 60,000 (I) and 15,000 (II) molecular weights, were obtained in Sephadex G100 column chromatography of the ammonium sulfate precipitate from the cytoplasmic extract. A third form III, 75,000 MW, was obtained from the culture filtrate. The activity of the enzyme was increased by Triton X-100 and was not inhibited byp-chloromercuribenzoate (PCMB), a sulfhydryl reagent. The enzymes I and II were inhibited differentially by NaCl. The optimal activities of forms I, II and III occurred at pH 4.8, pH 8.0 and pH 7.0, respectively. the apparent Km values of 7.7×10⁻⁵, 8.3×10⁻⁵ and 10.5×10⁻⁵, respectively, indicate a similar order of affinity for cholesteryl oleate at pH 7.1. The rate of hydrolysis of cholesteryl esters were in the order: linoleate>oleate>valerate>butyrate > acetate. Cholesteryl benzoate and palmitate were not hydrolyzed. The properties of the microbial enzyme are discussed in relation. Contribution no. 1098.     

Catheterization: a need for improved patient management

The complications arising from catheterization of the urinary bladder have been extensively researched and reviewed. It is widely accepted that, because of inherent risks, catheterization is a last resort in the management of urinary incontinence. However, anecdotal evidence suggests that the incidence of long-term catheterization for this purpose is increasing, particularly for the management of highly dependent patients in the community. Although catheterization is a common procedure, a high level of nursing knowledge and skill is required to achieve effective and safe management. This article reviews the principles of catheter management and the nurse's responsibility to the catheterized patient.